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1.
J Invertebr Pathol ; 196: 107870, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36493843

RESUMO

Larvae of the invasive pest Drosophila suzukii are susceptible to the Steinernema carpocapsae - Xenorhabdus nematophila complex and an assessment of the immune-regulatory system activation in this insect was performed to understand the response to the nematode infection. The expressions of 14 immune-related genes of different pathways (Imd, Toll, Jak-STAT, ProPO, JNK, TGF-ß) were analyzed using qRT-PCR to determine variations after nematode penetration (90 min and 4 h) and after bacterial release (14 h). Before the bacteria were present, the nematodes were not recognized by the immune system of the larvae and practically none of the analyzed pathways presented variations when compared with the non-infected larvae. However, after the X. nematophila were released, PGRP-LC was activated leading to the gene upregulation of antimicrobial peptides of both the Toll and Imd pathways. Interestingly, the cellular response was inactive during the infection course as Jak/STAT and pro-phenoloxidase genes remained unresponsive to the presence of both pathogens. These results illustrate how D. suzukii immune pathways responded differently to the nematode and bacteria along the infection course.


Assuntos
Rabditídios , Xenorhabdus , Animais , Drosophila , Larva/microbiologia , Xenorhabdus/genética , Simbiose , Rabditídios/genética
2.
Drug Metab Dispos ; 50(4): 327-340, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35042701

RESUMO

Lurbinectedin is a novel and potent selective inhibitor of active transcription of protein-coding genes, triggering apoptosis of cancerous cells. It has been approved for the treatment of patients with metastatic small-cell lung cancer with disease progression on or after platinum-based chemotherapy. Studies exploring the disposition and metabolism of lurbinectedin were performed in vitro and in vivo (by intravenous administration of lurbinectedin). Low blood cell partitioning for lurbinectedin in rats, nonhuman primates (NHP), and humans was determined as 23.4%, 29.8%, and 9.8%, respectively. Protein binding was very high (>95%) in total plasma (rat, NHP, and human), albumin, and α-1-acid glycoprotein (both human). In vitro, lurbinectedin underwent intense liver microsome-mediated metabolism-in 10 minutes, 80% of the compound is metabolized in human-with CYP3A4 being the isoform involved in that metabolism. Results also showed NHPs being the nonclinical species which, metabolically, most closely resembles humans. Mass balance studies performed in rats (both genders), NHPs (male only), and patients (both genders) demonstrated that the principal route of excretion of 14C-lurbinectedin-related radioactivity was through the feces (88.7% ± 10.1% in patients), with only a minor fraction recovered from the urine (5.6% ± 2.0% in patients). In plasma samples, the majority of lurbinectedin-related radioactivity was attributed to unchanged compound (95% ± 3.1% and 70.2% ± 10.9% in NHPs and humans, respectively). Plasma metabolic profiling demonstrated the major (% compared with unchanged compound) circulating metabolites were N-Desmethyl-lurbinectedin (0.4% ± 0.2% and 10.4% ± 2.2% in NHPs and patients, respectively) and 1',3'-Desmethylene-lurbinectedin (0.9% ± 0.7% and 14.3% ± 10.4% in NHP and patients, respectively). SIGNIFICANCE STATEMENT: Lurbinectedin is a novel and potent selective inhibitor of active transcription of protein-coding genes, triggering apoptosis of cancerous cells, and was recently approved for the treatment of patients with metastatic small-cell lung cancer with disease progression on or after platinum-based chemotherapy. The present study provides a complete set of information on the pharmacokinetics, biotransformation, and elimination of 14C-lurbinectedin and its metabolites, following a single intravenous administration to nonclinical species (rats and nonhuman primates) and patients.


Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Animais , Carbolinas/farmacologia , Carbolinas/uso terapêutico , Fezes , Feminino , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Masculino , Ratos , Carcinoma de Pequenas Células do Pulmão/induzido quimicamente , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Carcinoma de Pequenas Células do Pulmão/patologia
3.
J Dairy Sci ; 104(11): 11580-11592, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34454748

RESUMO

The continuous trend for a narrowing margin between feed cost and milk prices across dairy farms in the United States highlights the need to improve and maintain feed efficiency. Yeast culture products are alternative supplements that have been evaluated in terms of milk performance and feed efficiency; however, less is known about their potential effects on altering rumen microbial populations and consequently rumen fermentation. Therefore, the objective of this study was to evaluate the effect of yeast culture supplementation on lactation performance, rumen fermentation profile, and abundance of major species of ruminal bacteria in lactating dairy cows. Forty mid-lactation Holstein dairy cows (121 ± 43 days in milk; mean ± standard deviation; 32 multiparous and 8 primiparous) were used in a randomized complete block design with a 7-d adaptation period followed by a 60-d treatment period. Cows were blocked by parity, days in milk, and previous lactation milk yield and assigned to a basal total mixed ration (TMR; 1.6 Mcal/kg of dry matter, 14.6% crude protein, 21.5% starch, and 38.4% neutral detergent fiber) plus 114 g/d of ground corn (CON; n = 20) or basal TMR plus 100 g/d of ground corn and 14 g/d of yeast culture (YC; n = 20; Culture Classic HD, Cellerate Yeast Solutions, Phibro Animal Health Corp.). Treatments were top-dressed over the TMR once a day. Cows were individually fed 1 × /d throughout the trial. Blood and rumen fluid samples were collected in a subset of cows (n = 10/treatment) at 0, 30, and 60 d of the treatment period. Rumen fluid sampled via esophageal tubing was analyzed for ammonia-N, volatile fatty acids (VFA), and ruminal bacteria populations via quantitative PCR amplification of 16S ribosomal DNA genes. Milk yield was not affected by treatment effects. Energy balance was lower in YC cows than CON, which was partially explain by the trend for lower dry matter intake as % body weight in YC cows than CON. Cows fed YC had greater overall ruminal pH and greater total VFA (mM) at 60 d of treatment period. There was a contrasting greater molar proportion of isovalerate and lower acetate proportion in YC-fed cows compared with CON cows. Although the ruminal abundance of specific fiber-digesting bacteria, including Eubacterium ruminantium and Ruminococcus flavefaciens, was increased in YC cows, others such as Fibrobacter succinogenes were decreased. The abundance of amylolytic bacteria such as Ruminobacter amylophilus and Succinimonas amylolytica were decreased in YC cows than CON. Our results indicate that the yeast culture supplementation seems to promote some specific fiber-digesting bacteria while decreasing amylolytic bacteria, which might have partially promoted more neutral rumen pH, greater total VFA, and isovalerate.


Assuntos
Lactação , Rúmen , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Suplementos Nutricionais , Digestão , Eubacterium , Feminino , Fermentação , Fibrobacter , Leite , Gravidez , Rúmen/metabolismo , Ruminococcus , Saccharomyces cerevisiae , Succinivibrionaceae
4.
Metabolism ; 115: 154460, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33285180

RESUMO

BACKGROUND: Reproduction is tightly coupled to body energy and metabolic status. GnRH neurons, master elements and final output pathway for the brain control of reproduction, directly or indirectly receive and integrate multiple metabolic cues to regulate reproductive function. Yet, the molecular underpinnings of such phenomenon remain largely unfolded. AMP-activated protein kinase (AMPK), the fundamental cellular sensor that becomes activated in conditions of energy deficit, has been recently shown to participate in the control of Kiss1 neurons, essential gatekeepers of the reproductive axis, by driving an inhibitory valence in situations of energy scarcity at puberty. However, the contribution of AMPK signaling specifically in GnRH neurons to the metabolic control of reproduction remains unknown. METHODS: Double immunohistochemistry (IHC) was applied to evaluate expression of active (phosphorylated) AMPK in GnRH neurons and a novel mouse line, named GAMKO, with conditional ablation of the AMPK α1 subunit in GnRH neurons, was generated. GAMKO mice of both sexes were subjected to reproductive characterization, with attention to puberty and gonadotropic responses to kisspeptin and metabolic stress. RESULTS: A vast majority (>95%) of GnRH neurons co-expressed pAMPK. Female (but not male) GAMKO mice displayed earlier puberty onset and exaggerated LH (as surrogate marker of GnRH) responses to kisspeptin-10 at the prepubertal age. In adulthood, GAMKO females retained increased LH responsiveness to kisspeptin and showed partial resilience to the inhibitory effects of conditions of negative energy balance on the gonadotropic axis. The modulatory role of AMPK in GnRH neurons required preserved ovarian function, since the differences in LH pulsatility detected between GAMKO and control mice subjected to fasting were abolished in ovariectomized animals. CONCLUSIONS: Altogether, our data document a sex-biased, physiological role of AMPK signaling in GnRH neurons, as molecular conduit of the inhibitory actions of conditions of energy deficit on the female reproductive axis.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Metabolismo Energético/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Hormônio Luteinizante/sangue , Neurônios/metabolismo , Reprodução/fisiologia , Proteínas Quinases Ativadas por AMP/genética , Animais , Ciclo Estral/metabolismo , Feminino , Kisspeptinas/farmacologia , Masculino , Desnutrição/metabolismo , Camundongos , Camundongos Knockout , Neurônios/efeitos dos fármacos , Fosforilação , Caracteres Sexuais , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
5.
Arq. bras. med. vet. zootec. (Online) ; 72(5): 1911-1919, Sept.-Oct. 2020. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-1131533

RESUMO

Objetivou-se avaliar as alterações fisiológicas de ovinos submetidos à restrição alimentar, expostos à radiação solar e à sombra. Dez borregas mestiças foram divididas igualmente em dois grupos: grupo radiação solar - GRS, animais expostos ao sol durante o dia; e grupo sombra - GS, animais alocados dentro de um galpão à sombra. Nos seis dias iniciais de experimento, os animais foram submetidos à restrição alimentar, com acesso apenas à água, já expostos ao sol ou à sombra. Nos seis dias subsequentes, foi ofertada dieta composta por ração e feno de alfafa (3%PV). Os parâmetros avaliados foram frequência respiratória (FR), temperatura retal (TR), ß-hidroxibutirato (BHB), pH urinário, ingestão de matéria seca (IMS) e dados bioclimáticos (temperatura, umidade relativa do ar e índice de temperatura e umidade - ITU). A FR foi o parâmetro em que houve maior diferença significativa entre os grupos (p<0,05). O balanço energético negativo foi constatado em todos os animais (BHB>0,8mmol/L; pH<7,0). Ovelhas que sofrem restrição alimentar durante períodos de alta temperatura e umidade têm menor frequência respiratória e temperatura interna, independentemente de estar na sombra ou pleno sol. Porém, quando normalizado a oferta de alimento as ovelhas em pleno sol têm menor ingestão de matéria seca.(AU)


We aimed to evaluate physiological changes in sheep submitted to food restriction, exposed to the sun or shade. Ten ewe lambs were equally divided into two groups: Sun Radiation Group - GRS, exposed to sun during day hours, and Shade Group - GS, with animals placed inside a barn. In the first six days of experiment, animals were submitted to food restriction, with access to fresh water, already exposed to sun and shade. In the following six days alfalfa hay and concentrate were provided to the animals (3%BW). Parameters assessed were respiratory rate (FR), rectal temperature (TR), ß-hydroxybutyrate, urinary pH, dry matter intake (IMS) and climate data (air temperature, humidity, and temperature-humidity index - ITU). The parameter that most differed between groups was FR. All animals presented negative energy balance (BHB>0.8mmol/L; pH<7,0). Ewe lambs submitted to food restriction during periods of high temperature and humidity have lower respiratory rate and intern temperature, independently of being exposed to sun or shade. However, when food was offered animals exposed to sun had lower dry matter intake.(AU)


Assuntos
Animais , Temperatura Corporal/fisiologia , Ovinos/fisiologia , Transtornos de Estresse por Calor/fisiopatologia , Ácido 3-Hidroxibutírico , Restrição Calórica/veterinária , Taxa Respiratória , Resposta ao Choque Térmico/fisiologia , Transtornos de Estresse por Calor/veterinária
6.
Sci Rep ; 10(1): 13898, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807904

RESUMO

In addition to its essential role in the physiological control of longitudinal growth, growth-hormone (GH) is endowed with relevant metabolic functions, including anabolic actions in muscle, lipolysis in adipose-tissue and glycemic modulation. Adult obesity is known to negatively impact GH-axis, thereby promoting a vicious circle that may contribute to the exacerbation of the metabolic complications of overweight. Yet, to what extent early-overnutrition sensitizes the somatotropic-axis to the deleterious effects of obesity remains largely unexplored. Using a rat-model of sequential exposure to obesogenic insults, namely postnatal-overfeeding during lactation and high-fat diet (HFD) after weaning, we evaluated in both sexes the individual and combined impact of these nutritional challenges upon key elements of the somatotropic-axis. While feeding HFD per se had a modest impact on the adult GH-axis, early overnutrition had durable effects on key elements of the somatotropic-system, which were sexually different, with a significant inhibition of pituitary gene expression of GH-releasing hormone-receptor (GHRH-R) and somatostatin receptor-5 (SST5) in males, but an increase in pituitary GHRH-R, SST2, SST5, GH secretagogue-receptor (GHS-R) and ghrelin expression in females. Notably, early-overnutrition sensitized the GH-axis to the deleterious impact of HFD, with a significant suppression of pituitary GH expression in both sexes and lowering of circulating GH levels in females. Yet, despite their similar metabolic perturbations, males and females displayed rather distinct alterations of key somatotropic-regulators/ mediators. Our data document a synergistic effect of postnatal-overnutrition on the detrimental impact of HFD-induced obesity on key elements of the adult GH-axis, which is conducted via mechanisms that are sexually-divergent.


Assuntos
Dieta Hiperlipídica , Hormônio do Crescimento/metabolismo , Obesidade/etiologia , Hipernutrição/complicações , Caracteres Sexuais , Animais , Peso Corporal , Feminino , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Modelos Biológicos , Obesidade/genética , Especificidade de Órgãos , Hipernutrição/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Receptores da Somatotropina/genética , Receptores da Somatotropina/metabolismo
7.
Arq. bras. med. vet. zootec. (Online) ; 72(4): 1075-1084, July-Aug. 2020. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1129787

RESUMO

Calves are extremely dependent on colostrum intake for the acquisition of passive immunity. This study aimed to determine the occurrence of diarrhea and respiratory diseases and the impact of Failure of Passive Immune Transfer (FPIT) on the health and zootechnical performance of Holstein dairy calves in individual management. This study has been carried out in five commercial farms in Rio Grande do Sul State, Brazil, from March 2017 to January 2018. In this study, 131 calves were followed from birth to 60 days of age. Total Plasmatic Protein (TPP) has been performed to determine passive immune transfer quality in 53 calves (53/131). A daily clinical follow-up has been accomplished aiming at diagnosing diseases and their incidences, and zootechnical measures such as withers height, width of the croup and weight have been evaluated. FPIT rate was 32.07%, diarrhea occurrence and respiratory diseases were 77.9% and 49.6%, respectively. FPIT increased the chances of calves presenting diarrhea and developing respiratory diseases, but no differences on zootechnical performance were found. The frequency of FPIT is still high and is a factor that corroborated the increased risk for diarrhea and respiratory disease but did not influence the performance of calves in the preweaning phase.(AU)


Bezerras são extremamente dependentes da ingestão de colostro para adquirir imunidade passiva. Este estudo teve o objetivo de determinar os índices de ocorrência de diarreia e de doença respiratória, assim como o impacto da falha na transferência de imunidade passiva (FTIP) no desenvolvimento de doenças e no desempenho zootécnico de bezerras Holandês criadas em sistema individual. O estudo foi desenvolvido em cinco propriedades comerciais no Rio Grande do Sul, Brasil, entre março de 2017 e janeiro de 2018. Assim, 131 bezerras foram acompanhadas, do nascimento aos 60 dias de idade. Em 53 animais, foi realizada avaliação de proteínas plasmáticas totais para determinar a qualidade na transferência de imunidade passiva. Acompanhamento clínico diário foi realizado, a fim de diagnosticar doenças e suas incidências, assim como avaliações zootécnicas, como altura de cernelha, largura de garupa, perímetro torácico e peso. O percentual de FTIP foi 32,07%, a ocorrência de diarreias e de doenças respiratórias foi, respectivamente, 77,9% e 49,6%. A FTIP aumentou as chances de as bezerras apresentarem diarreia e doenças respiratórias, mas não alterou o desempenho zootécnico. Conclui-se que a frequência na FTIP ainda é elevada, fator que corroborou o aumento do risco para as diarreias e doença respiratória. Apesar disso, a FTIP não influenciou no desenvolvimento das bezerras na fase de aleitamento.(AU)


Assuntos
Animais , Feminino , Bovinos , Doenças Respiratórias/veterinária , Imunoglobulinas , Imunização Passiva , Colostro , Diarreia/veterinária , Animais Recém-Nascidos/imunologia , Brasil
8.
Arq. bras. med. vet. zootec. (Online) ; 72(2): 387-395, Mar./Apr. 2020. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-1128267

RESUMO

O objetivo deste estudo foi avaliar estratégias terapêuticas para o tratamento de infecções broncopulmonares, utilizando a enrofloxacina de ação rápida e sua associação com suporte e fluidoterapia endovenosa ou suporte e solução oral energética e eletrolítica, por meio da mensuração de parâmetros clínicos, hematológicos, bioquímicos e desenvolvimento corporal de neonatos bovinos. Foram utilizadas 35 bezerras da raça Holandesa, monitoradas desde o nascimento até a sexta semana de vida, divididas aleatoriamente nos grupos: grupo CONTROLE; grupo antibiótico; grupo antibiótico + suporte + fluidoterapia endovenosa; grupo antibiótico + suporte + solução oral; e grupo SUPORTE. Os parâmetros zootécnicos foram avaliados do nascimento até a sexta semana de vida, e os parâmetros hematológicos e bioquímicos foram avaliados zero, 24, 72 e 120 horas após diagnóstico da broncopneumonia. Os animais do grupo antibiótico + suporte + solução oral apresentaram menores níveis de eosinófilos e maiores níveis de neutrófilos segmentados em comparação aos animais dos demais grupos. Não houve diferença nos parâmetros zootécnicos avaliados. Neste estudo, o tratamento com antibiótico e solução oral ofereceu aos animais melhor aporte para combater a broncopneumonia, favorecendo o organismo a desenvolver uma resposta imune efetiva diante da infecção.(AU)


The objective of this study was to evaluate therapeutic strategies for treatment of bronchopulmonary infections using fast-acting enrofloxacin and its association with support and endovenous fluid or support and oral energy and electrolytic solution, by measuring clinical, hematological, biochemical and development parameters of bovine neonates. Thirty-five Holstein calves, monitored from birth to six weeks of age, were randomly divided into five groups: control group; antibiotic group; antibiotic group + support + intravenous fluid therapy; antibiotic group + support + oral solution; and support group. The performance parameters were evaluated from birth to the 6th week of age and hematological and biochemical parameters were evaluated 0, 24, 72 and 120 hours after diagnosis of bronchopneumonia. Calves of the antibiotic group + support + oral solution group presented lower levels of eosinophils and higher levels of segmented neutrophils compared to the other groups. There was no difference in performance parameters evaluated. In this study, the treatment with antibiotic and oral solution offered the animals had a better contribution to treat bronchopneumonia, favoring the organism to develop an effective immune response to that infection.(AU)


Assuntos
Animais , Recém-Nascido , Bovinos , Broncopneumonia/veterinária , Eletrólitos/administração & dosagem , Enrofloxacina/administração & dosagem , Hidratação/veterinária , Animais Recém-Nascidos
9.
Arq. bras. med. vet. zootec. (Online) ; 72(1): 153-160, Jan.-Feb. 2020. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-1088926

RESUMO

O objetivo do estudo foi avaliar a disponibilidade de cálcio (Ca2+) a partir de duas formas farmacêuticas (oral e intravaginal) e o seu efeito sobre o metabolismo de ruminantes. O estudo foi realizado na fazenda experimental da Universidade Federal de Pelotas, foram estudadas 24 ovelhas lactantes, divididas de forma randomizada em 4 grupos: dispositivo tratamento (DT); dispositivo controle (DC); oral tratamento (OT); e oral controle (OC). Os animais tratados receberam formiato de cálcio e cloreto de magnésio, as avaliações foram realizadas após a administração dos tratamentos. Foi feita avaliação de cálcio total (CaT), magnésio (Mg), proteínas plasmáticas totais (PPT), aspartato aminotransferase (AST), gama glutamil transpeptidase (GGT), ureia, albumina e pH urinário, e realizado exame clínico em todos os animais. As concentrações séricas de CaT, CaI e Mg diferiram entre os grupos (P≤ 0,05), os animais dos grupos DT e DC, diferiram nas três avaliações, o grupo DT apresentou as maiores médias, sendo significativamente igual ao grupo OT. Não houve diferença nas concentrações séricas de PPT, AST, GGT, Albumina, Ureia e pH urinário. Conclui-se que a disponibilidade sanguínea de CaT, CaI e Mg é igual quando a administração de formiato de cálcio e magnésio é por via intravaginal ou por via oral, sem alterar outros parâmetros metabólicos avaliados.(AU)


The aim of the study was to evaluate the availability of calcium (Ca2+) from two pharmaceutical forms (oral and intravaginal) and its effect on the metabolism of ruminants. The study was carried out at the experimental farm of the Federal University of Pelotas. Twenty-four lactating ewes were randomly divided into 4 groups: treatment device (TD); control device (DC); oral treatment (OT); and oral control (OC). Treated animals received calcium formate and magnesium chloride, evaluations were performed after administration of the treatments. Total calcium (CaT), magnesium (Mg), total plasma proteins (PPT), aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), urea, albumin and urinary pH, and clinical examination were performed on all animals. Serum CaT, CaI and Mg levels differed between the groups (P≤ 0.05), the animals in the DT and DC groups differed in the three evaluations, the DT group had the highest mean values, being significantly equal to the OT group. There was no difference in the serum concentrations of PPT, AST, GGT, Albumin, Urea and urinary pH. In conclusion, the blood availability of CaT, CaI and Mg is the same when administration of calcium and magnesium formate is intravaginal or orally, without altering other metabolic parameters evaluated.(AU)


Assuntos
Animais , Feminino , Administração Intravaginal , Ovinos/metabolismo , Cálcio/administração & dosagem , Hipocalcemia/veterinária , Magnésio/administração & dosagem
10.
Sci Rep ; 9(1): 9154, 2019 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235878

RESUMO

The possibility to detect fast neutrons as a distinct signal from that one of γ-rays background is surely of great importance for several topics, spanning from homeland security to radiation monitoring in nuclear physics research plants. Nowadays, Helium-3 based detectors are extremely expensive, while the use of large volume liquid scintillators presents serious concerns related to spillage risks and waste disposal. A very attractive alternative is the use of commercially available solid scintillators, which exploits an aromatic polymer matrix entrapping very high loadings of primary dye, thereby enabling the use of pulse shape analysis (PSA) to discriminate between fast neutrons and γ-rays. In this work, we analyse in detail the optical features of a solid scintillator composed by polymethylphenylsiloxane (PMPS) as base polymer loaded with moderate amounts of 2,5-diphenyloxazole (PPO). Furthermore, fluorescence decay kinetics have been correlated to the observed pulse shape discrimination capabilities of this radiation and thermally resistant scintillator, whose performances have been discussed in terms of conformational features and excimers formation revealed by the optical analyses.

11.
Res Vet Sci ; 124: 334-337, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31048181

RESUMO

The aims of the current study were to assess the inclusion levels of grape byproduct replacing jiggs hay in lambs diets and to evaluate signs of copper poisoning. Thirty-four Texel and Corriedale crossbred female lambs were used in a randomized block experimental design. The treatments comprised four levels of grape byproduct (0; 100; 200 and 300 g/kg DM) in replacement of jiggs hay. The diets were adjusted to the same ZnCu ratio (6:1) of the basal diet. Grape byproduct consumption at up to 30%, led to similar weight gain in the different treatments (P = .92), which was suitable for growing lambs. Grape byproduct in the diet had linear effect on GGT (P < .001) and AST (P < .0001) enzymes as well as on total bilirubin (P = .05). In addition, the highest grape byproduct addition showed the highest consumption of hay (P < .01). Hay replacement by grape byproduct at up to 300 g/kg in the DM was satisfactory to weight gain and did not negatively affect feed intake and weight gain of growing lambs. Maintaining zinc:copper ratio in sheep diets is not effective in preventing liver damage caused by increased dietary copper concentrations over a period of 70 days.


Assuntos
Cobre/intoxicação , Intoxicação por Metais Pesados/veterinária , Carneiro Doméstico/fisiologia , Vitis/química , Zinco/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Intoxicação por Metais Pesados/prevenção & controle , Zinco/administração & dosagem
12.
J Pharm Biomed Anal ; 169: 70-74, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30831452

RESUMO

A new method for the quantification of metabolites in the absence of a chemically synthetized authentic standard is described herein. Metabolites to be used as reference standards were obtained biologically from microsomes incubation. The method is a stepwise process in which, only the radiolabeled (14C) and non-radiolabeled parent compound are required. Briefly, the separation and principles of equimolar detection of LC-radioactivity were applied and, a calibration curve of the 14C-parent compound was used to quantify the formation of its 14C-metabolite. In turn, serial dilutions of this 14C-metabolite were the base for the calibration curve that allowed the quantification of the non-radiolabeled metabolite. This method was applied in plasma samples obtained from a dog pharmacokinetic study in which, a PharmaMar compound (lurbinectedin) and its N-desmethylated metabolite were quantified and, the results compared to those obtained by the classical approach (with the chemically synthetized N-desmethylated metabolite). Plasma concentrations obtained with the two methods were very similar, with standard relative errors between -11% to -4%. Similar, main pharmacokinetic parameters were calculated with the concentrations obtained either thru this method or by using a chemically synthetized authentic standard.


Assuntos
Análise Química do Sangue/métodos , Animais , Calibragem , Radioisótopos de Carbono/química , Cromatografia Líquida , Cães , Microssomos/química , Microssomos/metabolismo , Plasma/química , Padrões de Referência , Suínos , Porco Miniatura
13.
J Dairy Sci ; 102(1): 547-556, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30527989

RESUMO

This study was designed to evaluate the response of hematological and biochemical parameters submitted to pegbovigrastim administration and postchallenge with lipopolysaccharide (LPS). In experiment 1, 20 newborn Holstein calves were divided into 2 groups: the Imrestor (Elanco Saúde Animal, São Paulo, Brazil) group (IMR, n = 10), which received a 25 µg/kg of body weight (BW) subcutaneous administration of pegbovigrastim, and the control group (CTR, n = 10), which received a subcutaneous administration of 0.9% saline solution. Blood samples were collected on d 0, 10, 12, and 14 relative to birth to analyze the biochemical and hematological parameters. Moreover, growth measurements were taken on d 0, 7, 14, 21, and 60 relative to birth. The number of total leukocytes in the IMR group increased on d 12 and 14 in comparison to the CTR group, as well as the counts of segmented neutrophils, band cells, and monocytes. No differences were observed in the other hematological, biochemical, and growth parameters. In experiment 2, 20 Holstein calves from 30 to 60 d old were divided into 4 groups: group 1 (LPS, n = 5) received a 0.25 µg/kg of BW single intravenous dose of Escherichia coli LPS at d 0; group 2 (IMR, n = 5) received a 25 µg/kg of BW subcutaneous dose of pegbovigrastim at d 1; group 3 (IMR + LPS, n = 5) received a 0.25 µg/kg of BW intravenous LPS dose at d 0 and a 25 µg/kg of BW subcutaneous dose of pegbovigrastim at d 1; and group 4 (CTR, n = 5) received an intravenous dose of 0.9% sodium chloride at d 0 and a subcutaneous dose of 0.9% sodium chloride at d 1. For the analysis of biochemical and hematological parameters, blood samples were collected on d -1, 0, 1, 2, 3, 4, 8, 14, and 21 relative to LPS administration. An increase in the number of total leukocytes was observed in the IMR, IMR + LPS, and LPS groups, and the IMR group remained as the highest from d 2 to 21. The levels of paraoxonase 1 were higher in the IMR group compared with all the others. The administration of pegbovigrastim in the dairy calves increased the number of circulating leukocytes, especially neutrophils, with an increase in paraoxonase 1, without altering the metabolites for the hepatic function.


Assuntos
Anti-Inflamatórios/administração & dosagem , Bovinos/sangue , Fenilalanina/administração & dosagem , Administração Cutânea , Animais , Peso Corporal/efeitos dos fármacos , Brasil , Bovinos/crescimento & desenvolvimento , Feminino , Contagem de Leucócitos , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Fenilalanina/análogos & derivados , Gravidez
14.
Nat Commun ; 9(1): 4194, 2018 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-30305620

RESUMO

Puberty is regulated by epigenetic mechanisms and is highly sensitive to metabolic and nutritional cues. However, the epigenetic pathways mediating the effects of nutrition and obesity on pubertal timing are unknown. Here, we identify Sirtuin 1 (SIRT1), a fuel-sensing deacetylase, as a molecule that restrains female puberty via epigenetic repression of the puberty-activating gene, Kiss1. SIRT1 is expressed in hypothalamic Kiss1 neurons and suppresses Kiss1 expression. SIRT1 interacts with the Polycomb silencing complex to decrease Kiss1 promoter activity. As puberty approaches, SIRT1 is evicted from the Kiss1 promoter facilitating a repressive-to-permissive switch in chromatin landscape. Early-onset overnutrition accelerates these changes, enhances Kiss1 expression and advances puberty. In contrast, undernutrition raises SIRT1 levels, protracts Kiss1 repression and delays puberty. This delay is mimicked by central pharmacological activation of SIRT1 or SIRT1 overexpression, achieved via transgenesis or virogenetic targeting to the ARC. Our results identify SIRT1-mediated inhibition of Kiss1 as key epigenetic mechanism by which nutritional cues and obesity influence mammalian puberty.


Assuntos
Epigênese Genética , Kisspeptinas/genética , Fenômenos Fisiológicos da Nutrição , Obesidade/metabolismo , Maturidade Sexual , Sirtuína 1/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/metabolismo , Cromatina/metabolismo , Feminino , Histonas/metabolismo , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Camundongos Transgênicos , Modelos Biológicos , Neurônios/metabolismo , Estado Nutricional , Complexo Repressor Polycomb 2/metabolismo , Regiões Promotoras Genéticas , Ratos , Ratos Wistar , Fatores de Tempo
15.
Arq. bras. med. vet. zootec. (Online) ; 70(1): 73-81, Jan.-Feb. 2018. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-888071

RESUMO

The aim of this study was to evaluate the effect of pST injections on metabolism, testicular size, and sperm characteristics in young boars. Sixty 22-day old piglets were divided into two groups: pST (n=30) and Control (n=30). The pST group was submitted to pST injections (90µg/kg body weight) every three days up to 330 days of age. Blood collections were performed weekly. Testicular weight was measures at 22, 82, 142, 202 and 365 days of age. Libido and fresh semen characteristics were evaluated between 150 and 210 days of age. Semen characteristics were also evaluated during a 72h storage period (15ºC). Testosterone, albumin, and phosphorus blood concentrations were higher in the pST group (P<0.05). The pST group had a higher IGF-I concentration in seminal plasma (P=0.05) and higher testicular weight (P<0.001) compared to the Control group. The pST group had higher ejaculate volume (P<0.001), total sperm count (P=0.047) and number of inseminating doses/ejaculate (P=0.047). During the 72h storage period, the pST group had a lower number of morphological alterations (P<0.001) compared to the Control group. In sum, pST injection in young boars increased testosterone concentration, testicular size, and sperm quality.(AU)


O objetivo deste estudo foi determinar o efeito da administração de pST sobre o metabolismo, o tamanho testicular e a qualidade espermática de cachaços jovens. Foram usados leitões com 22 dias de idade, divididos em dois grupos: pST (n=30) e controle (n=30). O grupo pST foi submetido a injeções de pST (90µg/kg de peso vivo) a cada três dias até 330 dias de idade. Peso testicular foi avaliado aos 22, 82, 142, 202 e 365 dias de idade. Libido e qualidade do sêmen fresco foram avaliados entre 150 e 210 dias de idade. Qualidade espermática foi avaliada durante refrigeração (15ºC) por um período de 72 horas. Concentrações sanguíneas de testosterona, albumina e fósforo foram maiores no grupo pST (P<0,05). O grupo pST apresentou maior concentração de IGF-I no plasma seminal (P=0,05) e maior peso testicular, quando comparado ao grupo controle (P<0,001). O grupo pST apresentou maior volume espermático (P<0,001), concentração espermática (P=0,047) e número de doses espermáticas por ejaculado (P=0,047). Durante o período de 72 horas de refrigeração, o grupo pST teve menor número de patologias espermáticas (P<0,001). Assim, conclui-se que a administração de pST aumenta a concentração sanguínea de testosterona, o tamanho testicular e a qualidade espermática de cachaços jovens.(AU)


Assuntos
Animais , Masculino , Suínos/embriologia , Suínos/metabolismo , Hormônio do Crescimento/análise , Testículo , Análise do Sêmen/veterinária
16.
Arq. bras. med. vet. zootec. (Online) ; 70(4): 1129-1134, jul.-ago. 2018. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-916629

RESUMO

Métodos observacionais subjetivos, como escore de locomoção (EL) e escore de condição corporal (ECC), têm sido amplamente utilizados para avaliação populacional de diferentes graus de claudicação e estado nutricional em bovinos. Este estudo objetivou verificar a associação longitudinal entre o escore de condição corporal e o escore de locomoção em vacas da raça Holandesa submetidas a um regime alimentar semiextensivo. O período experimental compreendeu dois anos de observações, em uma propriedade localizada no sul do Rio Grande do Sul. O grupo experimental foi constituído por 900 vacas lactantes, que foram avaliadas trimestralmente por dinâmica ortopédica pelo EL e do estado metabólico pelo ECC. A coleta desses dados foi realizada por três veterinários treinados. A fim de se verificar a correlação entre variáveis, utilizou-se o programa SAS, por meio do método de correlação de Pearson, para determinar a associação entre as variáveis avaliadas (EL e ECC), com nível de significância de 5%. A distribuição dos diferentes escores de locomoção durante o período foi a seguinte: 57,2% dos animais tiveram o escore de locomoção 1, ou seja, estavam saudáveis em relação ao sistema locomotor. O restante dos animais que apresentou algum grau de dificuldade de locomoção distribuiu-se da seguinte forma, segundo a intensidade: 21,6% dos animais apresentaram EL2, 15,5% deles EL3, 3,5% deles EL4 e 2,2% deles EL5. Quanto ao resultado da correlação, observou-se associação negativa (r= -0,57) entre ECC e EL (P= 0,03), com ECC médio de 2,97±0,33 e EL de 1,35±0,24 durante o período experimental. Portanto, há uma correlação negativa entre o escore de condição corporal e o escore de locomoção em vacas da raça Holandesa submetidas ao regime alimentar semiextensivo.(AU)


Subjective observational methods such as locomotion score (LS) and body condition score (BSC) have been widely used for populations evaluation of different degrees of claudication and nutritional status in cattle. This study aimed to verify the longitudinal association between body condition score and locomotion score in Holstein cows submitted to a semi-extensive breeding regime. The experimental period comprised two years of observations at a property located in the South of Rio Grande do Sul. The experimental group consisted of 900 lactating cows, which were evaluated quarterly, being evaluated by orthopedic dynamics through LS and of the metabolic status through BCS. The collection of these data was performed by three trained veterinarians. To verify the correlation between variables, the SAS program was used using the Pearson Correlation method to determine the association between the variables evaluated (LS and BSC), at a significance level of 5%. The rest of the animals that showed some degree of locomotion difficulty, were distributed following intensity: 21.6% of LS2 animals, 15.5% of LS3 animals, 3.5% with LS4, and 2.2% with LS5, while 57,2% were without locomotion difficulty (LS1). Regarding the correlation result, a negative association (r= -0.57) was found between BSC and LS (P=0.03), with an overall of BSC of 2.97±0.33 and LS of 1, 35±0.24 during the experimental period. Therefore, there is a negative correlation between body condition score and locomotion score in Holstein cows submitted to the semi-extensive breeding regime.(AU)


Assuntos
Animais , Feminino , Bovinos , Ração Animal/análise , Composição Corporal , Bovinos/anatomia & histologia , Bovinos/metabolismo , Casco e Garras
17.
Arq. bras. med. vet. zootec. (Online) ; 69(5): 1130-1138, set.-out. 2017. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-877299

RESUMO

A hipótese do presente estudo consiste em que uma dieta aniônica prolongada acarretaria uma mobilização mais rápida do cálcio sanguíneo. O objetivo proposto foi avaliar parâmetros clínicos, hematológicos e bioquímicos de novilhas, com hipocalcemia subclínica, submetidas a diferentes períodos de fornecimento de dieta aniônica no pré-parto. Foram utilizadas nove novilhas da raça Holandês induzidas à hipocalcemia subclínica no pré-parto, divididas em três grupos: G0 = sem dieta aniônica antes da indução; G11 = 11 dias de dieta aniônica pré-indução; e G15 = 15 dias de dieta aniônica pré-indução. Foi realizado exame clínico antes e depois da indução, e avaliaram-se cálcio total e ionizado, magnésio e albumina nos dias -2, 0, 1, 2 e 3 (dia 0 = momento da indução) e parâmetros hematológicos nos dias 0, 1, 2 e 3. O G11 apresentou maiores concentrações de cálcio total e ionizado que o G0 e maiores níveis de cálcio total que o G15 (P<0,01). O magnésio teve maiores valores no G15 quando comparado aos outros grupos (P<0,01). O G0 apresentou os maiores valores de monócitos e neutrófilos bastonetes (P<0,01). A dieta aniônica por 11 dias é suficiente para manter a homeostase do cálcio e a resposta leucocitária em novilhas desafiadas a uma diminuição do cálcio sanguíneo.(AU)


This study's hypothesis is that cows receiving anionic diet for a longer period respond more quickly to decreased blood calcium. The aim was to evaluate the heifers' clinical, hematological, and biochemical parameters, with subclinical hypocalcemia, subjected to different periods of anionic diet supply during antepartum. Nine heifers were induced to subclinical hypocalcemia during antepartum, sorted in 3 groups: G0 = no anionic diet before induction; G11= eleven days of anionic diet before induction; and G15 = fifteen days of anionic diet before induction. Examinations were held before and after induction and total and ionized calcium, magnesium and albumin were evaluated from days -2, 0, 1, 2 and 3, day 0 being the moment of induction; hematologic parameters were evaluated at days 0, 1, 2 and 3. G11 presented a higher total and ionized calcium concentration than G0 and higher total calcium concentration than G15 (P < 0.01). Magnesium had its highest values at G15 when compared to the other two groups (P < 0.01). G0 presented its highest values of monocytes and neutrophils rods (P<0.01). The eleven days of anionic diet supply were enough to maintain calcium homeostasis and leukocyte response in heifers challenged to reduction in blood calcium.(AU)


Assuntos
Animais , Feminino , Gravidez , Bovinos , Cálcio da Dieta , Cálcio/sangue , Dieta/veterinária , Hipocalcemia/veterinária , Nutrição da Gestante
18.
Arq. bras. med. vet. zootec ; 69(2): 317-324, mar.-abr. 2017. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-833823

RESUMO

A hipótese deste estudo é de que o uso da combinação de butafosfan e cianocobalamina pode melhorar a resistência periférica à insulina, aumentar a quantidade de glicose disponível para a glândula mamária e a produção de leite. Assim, o objetivo foi investigar os efeitos combinados de butafosfan e cianocobalamina sobre o metabolismo da glicose em vacas leiteiras no período pós-parto. Vinte e uma vacas leiteiras foram divididas em dois grupos: grupo controle (CON, n= 11), que recebeu cinco aplicações de solução salina (20mL / animal 0,9% NaCl), e grupo Catosal(r) (ABC, n= 10), que recebeu cinco aplicações de 20mL de uma solução contendo as substâncias butafosfan e cianocobalamina (B12 Catosal(r), 100mg da substância butafosfan e 50µg de cianocobalamina por mL). As aplicações foram realizadas por via intramuscular, nos dias sete, 12, 17, 22 e 27 pós-parto. As amostras de sangue foram coletadas para a avaliação das concentrações plasmáticas de fósforo, glicose, ácidos graxos não esterificados (AGNE), albumina, aspartato aminotransferase (AST) e creatina quinase (CK). Nos dias oito e 28 pós-parto, os animais foram pesados e submetidos aos testes de tolerância à glicose e à insulina. O tratamento promoveu perda de peso (ABC 40,4kg, CON 10,73kg, P<0,05) e aumento da AST (ABC 62,92 ±3,31U/L, CON 53,11±3,49 U / L, P<0,05) e dos níveis de CK (ABC 134,09± 19,08U / L, CON 79,43 ± 18,27U / L). Os grupos não diferiram quanto ao metabolismo (área sob a curva) da glicose nos dias oito e 28, porém os animais tratados tiveram um aumento na glicemia (P<0,05) no dia 28 pós-parto (97,54 ± 8,54mg / dL), após a administração de insulina, em comparação ao dia oito (83,01 ± 8,54mg / dL). Assim, pode-se concluir que a combinação de butafosfan e cianocobalamina melhora a adaptação do metabolismo da glicose em vacas leiteiras no início da lactação.(AU)


The hypothesis of this study is that the combined use of butaphosphan and cyanocobalamin could enhance peripheral insulin resistance, increasing the amount of glucose available for the mammary gland and milk production. Thus, our aim was to investigate the combined effects of butaphosphan and cyanocobalamin on the glucose metabolism in dairy cows during the postpartum period. Twenty one dairy cows were divided into two groups: Control Group (CON, n= 11), that received 5 injections of saline solution (20mL/animal 0.9 % NaCl), and Catosal group (ABC, n= 10) which received 5 injections of 20mL of a Butafosfan and Cyanocobalamin solution (Catosal(r) B12, 100mg of Butafosfan and 50µg Cyanocobalamin for mL). The injections were performed by intramuscular route, on days 7, 12, 17, 22 and 27 postpartum. Blood samples were taken on these days to evaluate plasma concentrations of phosphorus, glucose, non-esterified fatty acids (NEFA), albumin, aspartate aminotransferase (AST) and creatine kinase (CK). On days 8 and 28 postpartum, the animals were weighted and subjected to the glucose tolerance and insulin challenge tests. The treatment promoted weight loss (ABC 40.4kg, CON 10.73kg, P< 0.05) and increased AST (ABC 62.92 ±3.31U/L, CON 53.11 ±3.49U/L, P< 0.05) and CK levels (ABC 134.09 ±19.08U/L, CON 79.43 ±18.27U/L). Glucose metabolism (area under the curve) did not differ (P> 0.05) among groups on days 8 and 28; however, ABC animals showed higher serum glucose levels (P< 0.05) after insulin administration on day 28 postpartum (97.54 ±8.54mg/dL) when compared to day 8 (83.01 ±8.54mg/dL). It could be concluded that the combined use of butaphosphan and cyanocobalamin interferes positively with the adaptation of glucose metabolism in dairy cows in early lactation.(AU)


Assuntos
Animais , Feminino , Bovinos , Metabolismo Energético/fisiologia , Fósforo/sangue , Período Pós-Parto , Vitamina B 12/metabolismo , Testes Hematológicos/veterinária , Resistência à Insulina
19.
J Dairy Sci ; 100(1): 213-223, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28341042

RESUMO

Sorghum silage has been shown to be a good alternative to corn silage for dairy cows; however, studies regarding heifers are insufficiently explored. Therefore, the objective of this study was to evaluate effects of changing forage to concentrate ratio (FOR:CON) in diets based on sorghum silage on N digestibility, rumen fermentation, N balance, C excretion, and microbial N yield in limit-fed dairy heifers. A split-plot 4×4 Latin square design with 19-d periods (15 d of adaptation and 4 d of sampling) was conducted with 8 rumen cannulated dairy heifers (age 13.7±0.6mo and weight 364.8±17.6kg). Heifers were fed sorghum silage-based diets with 4 FOR:CON (85:15, 75:25, 65:35, and 55:45) balanced for similar metabolizable energy intake per unit of body weight and crude protein concentration. Diets were fed to allow 900 to 1,000g/d body weight gain and were fed once daily. Total collection of feces and urine was completed on d 15 to 19 to determine N, C, urea N, allantoin, uric acid, and creatinine excretion. Rumen contents were sampled on d 19 at 0, 1.5, 3, 4.5, 6, 9, 13, 17, 21, and 23h after feeding to measure pH, volatile fatty acid (VFA), ammonia-N, and free AA concentrations. The pH decreased linearly while ammonia-N and free AA levels increased linearly with decreasing FOR:CON of diets. Although mean total VFA did not differ among treatment diets, molar proportions of VFA did. Acetate proportion decreased while propionate and butyrate increased with decreasing FOR:CON. Intake of N and urea N excretion decreased with decreasing forage proportion in diets while total N excretion, apparent N digestibility, and N retention were not different. Intake of C and excretion in feces (g/d) decreased linearly with decreasing FOR:CON in diets. Creatinine, allantoin, and uric acid excretion were not affected by FOR:CON; however, microbial N yield tended to increase linearly with greater concentrate in diets. Heifers limit fed diets based on sorghum silage demonstrated the effect of available ammonia-N and readily fermentable carbohydrates with subsequent effects on nutrient utilization when different FOR:CON were applied. Based on the presented results, FOR:CON 65:35 had the most suitable balance of available ammonia-N and readily fermentable carbohydrates for the most optimal results.


Assuntos
Rúmen/metabolismo , Silagem , Animais , Bovinos , Dieta/veterinária , Digestão , Feminino , Fermentação , Lactação , Purinas , Sorghum , Zea mays
20.
J Dairy Sci ; 100(1): 224-235, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28341043

RESUMO

Sorghum forage is an alternative crop that is more adapted to drier conditions and more resistant than corn to drought conditions. Thus, sorghum forage maximizes water utilization. The objective of this study was to evaluate sorghum silage (SS), including digestibility and fermentation parameters, in precision-fed dairy heifers. Eight Holstein heifers (13.7±0.6mo of age and 364.8±17.64kg of body weight) fitted with rumen cannulas were used in a replicated 4×4 Latin Square design; treatments were 4 levels of forage to concentrate ratios (85:15, 75:25, 65:35, and 55:45). Rumen contents were sampled at various times to determine pH and volatile fatty acid concentrations. Dry matter (DM) and neutral detergent fiber (NDF) in situ degradation kinetics were compared between SS and corn silage (CS) diets. Fecal total collection was used to estimate apparent total-tract digestibility. Fecal grab samples at 0, 6, 12, and 18h after feeding were used to estimate total-tract starch digestibility. Amount of concentrate in the diet affected the time that heifers spent eating as well as rumen pH. When the concentrate proportion of the diet increased, eating time and rumen pH decreased linearly. Total volatile fatty acid concentrations were not affected by treatment, but butyrate increased as the proportion of concentrate increased in the diet. Digestibility of DM and starch were higher in diets with lower forage to concentrate ratio, but NDF, acid detergent fiber, and hemicellulose digestibility were not affected. Corn silage had greater DM and NDF digestibility than SS. Also, fractional rate of digestion was faster for CS than SS (2.78 vs. 2.42% per hour, respectively). We conclude that fecal grab samples are suitable for predicting starch digestibility in heifers given the starch levels studied. In addition, SS was an adequate alternative forage in precision-fed dairy heifers with outcomes very similar to CS-based rations.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Sorghum , Animais , Bovinos , Dieta/veterinária , Fibras na Dieta/metabolismo , Digestão , Feminino , Lactação , Rúmen/metabolismo , Silagem , Zea mays/metabolismo
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